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Subject[PATCH v3 02/13] KVM: selftests: x86: Add a working xstate data structure
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Add a working xstate data structure for the usage of AMX and potential
future usage on other xstate components. AMX selftest requires checking
both the xstate_bv and xcomp_bv. Existing code relies on pointer
arithmetics to fetch xstate_bv and does not support xcomp_bv.

So, add a working xstate data structure into processor.h for x86.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
---
.../selftests/kvm/include/x86_64/processor.h | 12 +++++++
tools/testing/selftests/kvm/x86_64/amx_test.c | 36 ++++++-------------
2 files changed, 23 insertions(+), 25 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index b1a31de7108a..5cfd7ef40d78 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -45,6 +45,18 @@
#define X86_CR4_SMAP (1ul << 21)
#define X86_CR4_PKE (1ul << 22)

+struct xstate_header {
+ u64 xstate_bv;
+ u64 xcomp_bv;
+ u64 reserved[6];
+} __attribute__((packed));
+
+struct xstate {
+ u8 i387[512];
+ struct xstate_header header;
+ u8 extended_state_area[0];
+} __attribute__ ((packed, aligned (64)));
+
/* Note, these are ordered alphabetically to match kvm_cpuid_entry2. Eww. */
enum cpuid_output_regs {
KVM_CPUID_EAX,
diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c
index bd72c6eb3b67..bb9dc0008f43 100644
--- a/tools/testing/selftests/kvm/x86_64/amx_test.c
+++ b/tools/testing/selftests/kvm/x86_64/amx_test.c
@@ -41,10 +41,6 @@

#define XSAVE_HDR_OFFSET 512

-struct xsave_data {
- u8 area[XSAVE_SIZE];
-} __aligned(64);
-
struct tile_config {
u8 palette_id;
u8 start_row;
@@ -103,13 +99,13 @@ static inline void __tilerelease(void)
asm volatile(".byte 0xc4, 0xe2, 0x78, 0x49, 0xc0" ::);
}

-static inline void __xsavec(struct xsave_data *data, uint64_t rfbm)
+static inline void __xsavec(struct xstate *xstate, uint64_t rfbm)
{
uint32_t rfbm_lo = rfbm;
uint32_t rfbm_hi = rfbm >> 32;

asm volatile("xsavec (%%rdi)"
- : : "D" (data), "a" (rfbm_lo), "d" (rfbm_hi)
+ : : "D" (xstate), "a" (rfbm_lo), "d" (rfbm_hi)
: "memory");
}

@@ -158,16 +154,6 @@ static void set_tilecfg(struct tile_config *cfg)
}
}

-static void set_xstatebv(void *data, uint64_t bv)
-{
- *(uint64_t *)(data + XSAVE_HDR_OFFSET) = bv;
-}
-
-static u64 get_xstatebv(void *data)
-{
- return *(u64 *)(data + XSAVE_HDR_OFFSET);
-}
-
static void init_regs(void)
{
uint64_t cr4, xcr0;
@@ -184,7 +170,7 @@ static void init_regs(void)

static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg,
struct tile_data *tiledata,
- struct xsave_data *xsave_data)
+ struct xstate *xstate)
{
init_regs();
check_cpuid_xsave();
@@ -205,9 +191,9 @@ static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg,
__tilerelease();
GUEST_SYNC(5);
/* bit 18 not in the XCOMP_BV after xsavec() */
- set_xstatebv(xsave_data, XFEATURE_MASK_XTILEDATA);
- __xsavec(xsave_data, XFEATURE_MASK_XTILEDATA);
- GUEST_ASSERT((get_xstatebv(xsave_data) & XFEATURE_MASK_XTILEDATA) == 0);
+ xstate->header.xstate_bv = XFEATURE_MASK_XTILEDATA;
+ __xsavec(xstate, XFEATURE_MASK_XTILEDATA);
+ GUEST_ASSERT(!(xstate->header.xstate_bv & XFEATURE_MASK_XTILEDATA));

/* xfd=0x40000, disable amx tiledata */
wrmsr(MSR_IA32_XFD, XFEATURE_MASK_XTILEDATA);
@@ -244,7 +230,7 @@ int main(int argc, char *argv[])
struct kvm_run *run;
struct kvm_x86_state *state;
int xsave_restore_size;
- vm_vaddr_t amx_cfg, tiledata, xsavedata;
+ vm_vaddr_t amx_cfg, tiledata, xstate;
struct ucall uc;
u32 amx_offset;
int stage, ret;
@@ -284,10 +270,10 @@ int main(int argc, char *argv[])
tiledata = vm_vaddr_alloc_pages(vm, 2);
memset(addr_gva2hva(vm, tiledata), rand() | 1, 2 * getpagesize());

- /* xsave data for guest_code */
- xsavedata = vm_vaddr_alloc_pages(vm, 3);
- memset(addr_gva2hva(vm, xsavedata), 0, 3 * getpagesize());
- vcpu_args_set(vcpu, 3, amx_cfg, tiledata, xsavedata);
+ /* XSAVE state for guest_code */
+ xstate = vm_vaddr_alloc_pages(vm, DIV_ROUND_UP(XSAVE_SIZE, PAGE_SIZE));
+ memset(addr_gva2hva(vm, xstate), 0, PAGE_SIZE * DIV_ROUND_UP(XSAVE_SIZE, PAGE_SIZE));
+ vcpu_args_set(vcpu, 3, amx_cfg, tiledata, xstate);

for (stage = 1; ; stage++) {
vcpu_run(vcpu);
--
2.39.2.637.g21b0678d19-goog
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